1. Field of Endeavor
The present invention relates to sampling and more particularly to aerosol sampling.
2. State of Technology
U.S. Pat. No. 5,040,424 to Virgil A. Maple, et al patented Aug. 20, 1991 and assigned to Regents of the University of Minnesota provides the following state of technology information, xe2x80x9cIn recent years the Environmental Protection Agency (EPA) has established that a particle separating inlet which removes all of the particles that are larger than 10 microns from the flow before collecting the particles for analyzers should be developed. The sampling characteristics for such inlet must be substantially insensitive to wind direction and wind speed. The Federal Register, Volume 49, No. 55 for Tuesday Mar. 20, 1984 contains the proposed rules for testing such sampler inlet.xe2x80x9d
U.S. Pat. No. 5,183,481 to William Felder patented Feb. 2, 1993 and assigned to Aerochem Research Laboratories provides the following state of technology information, xe2x80x9cThe separation and collection of fine particles from gases is of intense interest in material sciences where fine particles may have unique and valuable properties. Often such particles are produced along with byproduct vapors in high temperature environments. It is frequently of importance to preserve the purity of the particles by separating them from the byproduct vapors which may condense on them if the particles are simply filtered. The separation and collection of fine particles from gases is also important in preventing such particles from entering the atmosphere as an unintended consequence of manufacturing or power generation processes, as in the manufacture of cements and the fly ash produced from coal-fired electrical generators. Large investments are made in filtration systems and/or high voltage electrical devices to separate and collect the fine particles that can cause pollution. The separation and collection of fine particles from gases is also important in research on atmospheric aerosols and particulates and in preparing powders comprising particles of uniform size for such applications as advanced materials processing.xe2x80x9d
U.S. Pat. No. 5,425,802 to Robert M. Burton et al patented Jun. 20, 1995 and assigned to The United States of America as represented by the Administrator of Environmental Protection Agency President and Fellows of Harvard provides the following state of technology information, xe2x80x9cParticle classification according to aerodynamic size can be carried out with a number of different devices, including elutriators, cyclones, centrifuges and impactors. Inertial impactors have been widely used for particle collection, mainly because of their sharp cut-off characteristics.xe2x80x9d
U.S. Pat. No. 6,402,817 to Warner Bergman patented Jun. 11, 2002 and assigned to The Regents of the University of California provides the following state of technology information, xe2x80x9cImpactors belong to a class of instruments called inertial classifiers, which separate particles in a fluid stream based on the inertia of particles. In general these instruments operate by forcing a change in the direction of the fluid stream containing the particles. Because of the particles inertia the particles cannot follow the fluid stream. If an obstacle is placed in the path of the fluid stream, the fluid is deflected around the obstacle while the particles are less able to deflect around the obstacle. If the particle inertia exceeds a minimum quantity, the particle cannot deflect around the obstacle and will be caught by the obstacle.xe2x80x9d
Features and advantages of the present invention will become apparent from the following description. Applicants are providing this description, which includes drawings and examples of specific embodiments, to give a broad representation of the invention. Various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this description and by practice of the invention. The scope of the invention is not intended to be limited to the particular forms disclosed and the invention covers all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims.
The present invention provides an environmental sampling system for sampling air and collecting sample particles of a predetermined particle size range from the air. A low pass section has an opening for gathering the air. The opening excludes particles larger than the desired sample particle size. The low pass section produces a total air flow that contains the sample particles. An impactor section is connected to the low pass section and receives the total air flow. The impactor section separates the total air flow into a bypass air flow that excludes particles smaller than the desired size range and a product air flow containing the sample particles. A wetted-wall cyclone collector is connected to the impactor section and receives the product air flow. The wetted-wall cyclone collector traps the sample particles of a predetermined particle size range are concentrated in the liquid.
The invention is susceptible to modifications and alternative forms. Specific embodiments are shown by way of example. It is to be understood that the invention is not limited to the particular forms disclosed. The invention covers all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims.